Sex and HIV education programs that are based on a written curriculum and that are implemented among groups of youth in schools, clinics, or other community settings are a promising type of intervention to reduce adolescent sexual risk behaviors. This paper summarizes a review of 83 evaluations of such programs in developing and developed countries. The programs typically focused on pregnancy or HIV/STI prevention behaviors, not on broader issues of sexuality such as developmental stages, gender roles, or romantic relationships. The review analyzed the impact these programs had on sexual risk-taking behaviors among young people.